Extra! Extra! Newsprint is compostable.

Dear Umbra,

Two questions: Does the colored ink in newspapers still contain
chemicals bad for a compost pile? Also, what about the colored ink
printed on cardboard boxes? I want to have a safe compost pile to use in
a garden.


Dearest Mysterious Reader,

Some readers may find gardening questions in February a bit jarring. By
choosing to answer this one, I'm taunting those of you who don't live in
the Pacific Northwest. True, we may be moistly imprisoned under an
unrelenting steely sky, daylight may be a dim memory, and mildew may be
our constant companion, but at least we can consider composting in
February. Ahh, compost. So helpful in relieving seasonal affective

Extra! Extra! Newsprint is compostable.
Pigments combine with a "vehicle" and a "binder" to create specific
inks for various printing projects. The pigment and the vehicle are the
bad boys. Paper composting and mulching is haunted by the specter of the
heavy metals used as pigment in commercial inks in the past. For years,
the vehicle was petroleum-based, but the industry is slowly switching
over to soy- or vegetable-based inks. However, inks labeled "soy-based"
are still permitted (and likely) to contain some amount of petroleum.

Pigments themselves still contain heavy metals such as zinc and copper,
although overall amounts of heavy metals have been reduced. Although
toxins are present in quite small amounts, all the sources I consulted
agreed that contemporary printed newsprint, including colored newsprint,
and cardboard boxes are safe for garden use. Glossy inserts, shiny ink
of any sort, magazines, and colored paper do not make appropriate
compost or mulch materials, due to a higher prevalence of toxics within
the paper and ink, and likelihood of "de-inking" (ink sliding off the
paper into your garden).

One further thing: If you're gardening in an urban or suburban area,
ink is a drop in the contamination bucket. It's far more likely that
your soil will be contaminated by other sources, such as lead paint,
pavement runoff, or car exhaust that washes from building walls into the
soil. Get your soil tested for heavy metals before food gardening and
avoid food gardening within 10 feet of a building. What is toxic is
often invisible to the eye.


We at Greenspieler really like Umbra. Thank you Umbra once again for imparting us with your wisdom!

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